I'm trying creating template for intrusive double-linked list:

mixin template node() {
  static if(is(this == struct))
    alias typeof(this)* E;
  else
    alias typeof(this) E;
  E prev, next;
}

struct list(alias N) {
  N.E head;
  N.E tail;
}

class A {
  mixin node;
}

list!A l;

All works great.
If it's need to store one object in two different lists I plan something like this:

class A {
  mixin node L1;
  mixin node L2;
}

list!(A.L1) l1;
list!(A.L2) l2;

But compiler doesn't compile that whith error:
"this is not in a class or struct scope|"
in line with
"alias typeof(this) E;"

On 2012-11-11 10:04, Jack Applegame wrote:
> I'm trying creating template for intrusive double-linked list:
>
> mixin template node() {
>    static if(is(this == struct))
>      alias typeof(this)* E;
>    else
>      alias typeof(this) E;
>    E prev, next;
> }
> class A {
>    mixin node L1;
>    mixin node L2;
> }

This won't work. The "node" template doesn't evaluate to a type and you wouldn't use it as a mixin if it did.

> But compiler doesn't compile that whith error:
> "this is not in a class or struct scope|"
> in line with
> "alias typeof(this) E;"
>



-- 
/Jacob Carlborg

On Sunday, 11 November 2012 at 10:36:42 UTC, Jacob Carlborg wrote:
> This won't work. The "node" template doesn't evaluate to a type and you wouldn't use it as a mixin if it did.
>
But this is works! Why?

mixin template node() {
  alias int E;
  E prev, next;
}

struct list(alias N) {
  N.E head;
  N.E tail;
}

class A {
  mixin node L1;
  mixin node L2;
}

list!(A.L1) l1;
list!(A.L2) l2;

On Sunday, 11 November 2012 at 10:36:42 UTC, Jacob Carlborg wrote:
> This won't work. The "node" template doesn't evaluate to a type and you wouldn't use it as a mixin if it did.

You _can_ actually use an identifier for mixin templates, it is used to disambiguate in case of name collisions.

As far as the original question goes, I don't see a reason why this shouldn't work; you might want to add a bug report at http://d.puremagic.com/issues.

David